An MRAM as an integrated magnetic memory is attracting attention as an unlimitedly programmable memory having an integrating density equal to that of a DRAM and a high speed equal to that of an SRAM. Also, the development of a thin-film magnetic head, magnetic sensor, and the like using magnetoresistive effect elements such as a GMR (Giant Magnetic Resistance) element and TMR (Tunneling Magnetic Resistance) element is rapidly progressing.
In an example of the magnetoresistive effect elements, a lower electrode is formed on a substrate made of, for example, silicon or glass, and a multilayered film having eight layers forming a magnetoresistive effect element (TMR) is formed on the lower electrode. An example of this multilayered film having eight layers is formed by sequentially stacking a PtMn layer as an antiferromagnetic layer, a magnetization fixed layer (Pinned Layer, Ru, pinned Layer), an insulating layer (Barrier Layer), a free layer, and a protective layer (hard mask) on a Ta layer as the lowermost underlying layer.
Methods have been proposed to obtain necessary performance of a magnetoresistive effect element by processing a substrate having a multilayered magnetic film forming the element by thin-film processing techniques such as reactive ion etching (RIE) and ion beam etching (IBE) developed in the semiconductor industry (see patent references 1 to 3).
As a processing technique using reactive ion etching among these techniques, the present applicant has proposed a method using alcohol (e.g., methanol) having at least one hydroxyl group as an etching gas. This method achieves the effects of increasing the etching rate and reducing damage mainly caused by oxidation after etching, compared to the conventional method using carbon monoxide gas to which ammonia gas is added (patent reference 3).
The present applicant has also proposed apparatuses in which a plasma generation chamber for generating a plasma and a substrate processing chamber for loading and processing a substrate are partitioned by a partition plate having a plurality of through holes, the plasma generation chamber generates a radical, and the substrate surface is processed by the radical having passed through the partition plate (patent references 4 to 13).    Patent reference 1: Japanese Patent Laid-Open No. 2003-203313    Patent reference 2: Japanese Patent Laid-Open No. 2004-326831    Patent reference 3: Japanese Patent Laid-Open No. 2005-42143    Patent reference 4: Japanese Patent Laid-Open No. 2000-345349    Patent reference 5: Japanese Patent Laid-Open No. 2002-83806    Patent reference 6: Japanese Patent Laid-Open No. 2002-212732    Patent reference 7: Japanese Patent Laid-Open No. 2002-212736    Patent reference 8: Japanese Patent Laid-Open No. 2002-246386    Patent reference 9: Japanese Patent Laid-Open No. 2003-197620    Patent reference 10: Japanese Patent Laid-Open No. 2004-111506    Patent reference 11: Japanese Patent Laid-Open No. 2004-296638    Patent reference 12: Japanese Patent Laid-Open No. 2005-268396    Patent reference 13: Japanese Patent Laid-Open No. 2006-49544